Monitored Anesthetic Care (MAC) Using Ketamine, Midazolam and a Target-Controlled Propofol Infusion for Minor Surgery

Kim, Sang Tae; Lim, Seung Woon

Abstract

BACKGROUND: There are many kinds of anesthetic methods. One of them, monitored anesthetic care (MAC) is a useful tool for minor surgery. Whether MAC can be substituted for conventional anesthesia in minor surgery was investigated.
METHODS
Sixty-five patients were studied. Midazolam was given intravenously as a premedication, and then, target-controlled infusion (TCI) using propofol was started and ketamine 25 mg was given intravenously before a painful stimuli. The initial target concentration of propofol was 2.5 microgram/ml. During the procedure, we adjusted the target concentration of propofol according to clinical signs and sometimes added 25 mg of ketamine intravenously. For 10 minutes after starting the propofol infusion, blood pressure, heart rate, SpO2 and respiratory rate were recorded. During recovery, we monitored the predicted concentrations of propofol at eye opening and orientation recovery, the time from stopping the propofol infusion and intraoperative complications. In addition, we checked the patient's satisfaction with the anesthesia.
RESULTS
The average consumption of ketamine and propofol were 0.68 +/- 0.43 mg/kg and 9.0 +/- 2.1 mg/kg/hr, respectively. The time to eye opening and recovery of orientation were 9.5 +/- 5.5 min and 10.2 +/- 5.3 min, respectively. The predicted plasma concentrations at eye opening and orientation recovery were 0.98 +/- 0.34 microgram/ml and 0.93 +/- 0.28 microgram/ml, respectively. Most patients (87.7%) were satisfied with the anesthetic method. However during the procedure, airway obstruction was the most frequent (21.5%) comlication.
CONCLUSIONS
MAC is a useful and excellent anesthetic method, but corresponding anesthesiologists must attend closely and monitor respiratory complications.